Art of producing musical tones.



M. L. SEVERY & G. B. SINCLAIR.

ART OF PRODUCING MUSICAL TONES.

APPLICATION FILED IAN. I0. I9I0.

Patented May 2, 1916.

3 SIIEETSSHEET I.

M. L. SEVERY & G. B. SINCLAIR.

ART OF PRODUCING MUSICAL TONES.

APPLICATION FILED JAN. 10. 1910.

1,181 ,486. Patented May 2,1916.

3 SHEETS-SHEET 2.

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Geo rye B. Sindaw /%M M. L. SEVERY & G. B. SINCLAIR.

ART OF PRODUCING MUSICAL TONES. APPLICATION FILED JAN.10.1910.

1, 181 ,486. Patented May 2,1916.

3 SHEETS-SHEET 3.

vvifiqesses; IH'VEWQ/X'SJ I I :Af6l17inL.S617 y Q 25.5 v emge In M)UNITED STATES PATENT OFFICE.

MELVIN SEVERY, OF ARLINGTON HEIGHTS, AND GEORGE B. SINCLAIR, OF MEDFORD,

MASSACHUSETTS; ASSIGNORS TO CHORALCELO COMPANY, OF BOSTON, MASSACHU-SETTS, CORPORATION OF MAINE.

v ART OF PRODUCING MUSICAL TONES.

Specification of Letters Patent.

' Patented May 2, 1916.

Application filed January 10, 1910. Serial No. 537,257.

To all whom it may concern Be it known that we, MELVIN L. SEVERY, ofArlington Heights, and GEORGE B. SIN- CLAIR, of Medford, each in thecounty of Middlesex and Commonwealth of Massachusetts, both citizens ofthe United States, have invented new and useful Improvements in the Artof Producing Musical Tones, of which the following is a specification. I

The object of this invention is the educing of composite musical tonesfrom tuned sonorous bodies, such as piano strings and the like, in orderthat the same sonorous body may at will be caused to emit a plurality ofwidely differing tone-qualities or timbres.

By means of our method or art, we are enabled to cause the sonorousbodies of a musical instrument to sound like a pipe organ, a violin, aflute, and other well known instruments, either singly or combined, atthe pleasure of the operator.

In the following description and in the claims, the word tone is used asmeaning sound, in relation to volume, quality and pitch; or as meaning asound that maybe.

employed in music, having a definite pitch,

and due to vibration of a' sounding body. I

As most tones are composite, consisting of several relatively simpleconstituents called partial tones, of which the lowest is usually themost prominent and is hence called the principal or fundamental tone,while the others are called accessory tones, overtonesor harmonics, itbecomes necessary at points in the description and claims further todefine or qualify the word tone by reference to the timbre, quality orpeculiar characteristic sound produced. The term tone is thus used inpreference to note for the reason that, according to accepteddefinitions of recognized dictionaries, such as the Standard, theCentury and W ebsters, tone properly pertains to thesound itself withits variations in pitch. loudness and timbre or quality, whereas note ismore appropriately applied to the sign or symbol indicating orrepresenting a given tone or sound, though as stated by these severalauthorities, the terms are loosely but incorrectly used interchangeably.

Referring to the drawings forming part of this specification: Figure 1is a perspective diagrammatic View of apparatus by means of which we areenabled to carry out our method or art; Fig. 2 is a diagram in plan viewof our apparatus for the production of the desired musical tones from asingle set of sonorous bodies, here repre sented as vibrating strings;Fig. 3 is a side sectional elevation of apparatus for the production ofcomposite tones by a single sonorous body; and Fig. 4 is a view of ourpreferred form of action brush and contact.

It has long been well known that musical sounds can be produced bythrowing into vibration any tuned sonorous body,.and that such vibrationmay be eiiected percussion, by friction, by electromagnetic attraction,and in other ways, and where such bodies are not of material capable ofdirect magnetic attraction, they have been provided with armatures ofsoft iron, steel, or other magnetically attractable substance, asproposed, for instance, in the patent to Ohmart, No. 472,079, datedMarch 29, 1892. It is hence to be understood that the vibrating stringhere represented is merely used as a type or illustration, and that anytuned sonorous body is comprehended within our invention. and may beemployed in lieu of the stretched string.

The first steps of our method or art, whereby we produce a plurality ofdifferent sonorous vibrations in a single body, are most clearlyillustrated by the apparatus set forth in Fig. 3. Here the sonorous bodyselected is a stretched string 1, either of magnetically attractablematerial, or rendered capable of magnetic attraction in any common andusual way and arranged within the field of attraction of anelectromagnet or magnets 2, in circuit-with a source of electric energy,the current from which is delivered in a series of pulsations. Thesemagnetic pulsations are engendered in said magnet by a pulsation devicecomprising the peripherally interrupted disk 3,-rotated at constant andproper speed in contact with a brush 4, introduced in the circuitbetween a current-source 5 and said electromagnets 2. Such circuit inoperation consists of a lead wire 6, brush 7, disk 3, brush 4, and wire8, to said electromagnet 2; and from the latter, of wires 9, 10, contact11, brush 12 and wire 13 back to the source The last-named brush ismoved into touch with said contact and the circuit thereby completed. bymeans of a key ll acting through the post 15 aml lever 10.

By having the speed of the disk 3 and the number of its peripheralinterruptions proportioned to accurately time such current interruptionsto the normal vibrations of.

the tuned string 1, the latter will be electromagnetieally sounded withits maximum loudness and purity of tone. If, now, we rotate the disk 3with just double its former speed, the magnetic pulsations communicatedto the electromagnet 2 and the number of vibrations imparted to thestring 1, will cause the latter to emit a note an octave higher but ofan entirely different timbre orquality. So, also, if certain otherfrequencies of pulsations are impressed upon the magnet. impartingcorresponding vibrations to the string, it will yield tones of differentpitches and qualities. If in addition to such electromagneticallyproduced vibration, the string be percussively actuated by means of thehammer 20 operated by the key 14. a still richer tone will be produced,the strongly marked fundamental of the string combining with the toneselectrically maintained, and giving a result of marvelous effect.Moreover, by having all the strings of the instrument similarlycontrolled. the effect of a plurality of simultaneously played musicalinstruments is produced.

lVe have further discovered that a plurality of different frequenciescan be simultaneously transmitted to the electromagnet 2, and the stringmade to vibrate accordingly and emit a tone of correspondingly differenttimbre or quality.

This may be done by providing one or more additional disks 3 withdifferently spaced peripheral interruptions, each with its brush 4 wiredto or in circuit with the electromagnet 2. The wire 8 being providedwith a variable resistance 8", the intensities of the differentpulsations can be varied at will and the resultant tone cduced from thestring equally changed. certain harmonics being made prominent andothers subdued. It is obvious. of course. that the wire 8 mightsimilarly be provided with a resistance. though we have omitted it inthe drawings for the sake of simplicity. t uch electromagneticresultants can be impressed upon or caused to vibrate the strings eitherin conjunction with the percussiveaction of the hammers, or without thesame, according to the desire of the player. In withdrawing the hammersfrom operative relation to the strings in order that the depression ofthe keys 14 may control only the electric actuations, it

I is only necessary to give a partial turn to the rockshaft-Ql, andthereby withdraw the upper end of the post or striker 15 from ongagementwith the member 22 of the action.

Each brush 1?. as shown more clearly in Fig. 4-. is preferably formedwith contact points of unequal length, and is caused to traverse twocontacts 11 and 11, the latter of which is joined directly to the wires10 and 9. but the first of which is connected with the wire 9 through aresistance 2 The purpose of this is to vary at will the current to themagnet 2, and to reduce the sparking which would otherwise occur as thebrushes lea ve the contacts ll and 11, the brushes 12 being soconstructed as to contact with 11 before leaving contacts 11. Towithdraw the individual dampers 25 from the strings 1 both when the sameare percussivcly and when they are elcctromagnctically vibrated. eachdamper has pivotally mounted beneath its tail a lever-arm 26 carrying aspoon 27 engaging such tail. This lever arm is depressed either by theswinging of said member 22 when the hammer associated therewith isoperated. or by the downward movement of the armature 28 joined to saidlever 26 by a link 99. as such armature responds to the electromagnet 30fixed beneath it. This electromagnet is energized simultaneously withthe energizing of the elcctromagnet 2. To accomplish this. eachmagnet'ilf) has one end of its coil connected with the wire 6 by a wireor conductor ill. which may be common to the several magnets. Theopposite end of the coil or windingof each of said magnets 30 isconnected to the wire 10 by an individual wire 32, or is directlyconnected with the contact 11 associated with the string 1 Whose dampersaid magnet controls. The lever arms 26 being pivotally supportedindependently of their associated members 22, the dampers can be movedelectrically even when the hammer actions are disconnected from thekeys, and said members remain quiet. As also shown in Fig. 3, thebrushes 4 are of an appreciable thickness, the same being indicated bythe two dotted radial lines. Consequently, a conducting section or tooth34 will remain in circuit with such brush for a space additional to itsown length equal to such contacting thickness of brush. The result is,if the low resistance sections 34 exactly equal the high resistancesections 35. that the electromagnet 2 will continue to attract itsstring 1 after the latter has begun its recession therefrom. with theeffect of retarding the movement of the string and reducing its sonorousstrength as well as af fecting its tonal quality. To obviate thisretardation, our invention further consists in making the time of eachenergization of the electromagnet 2 preferably exactly equal to and, forbest results, in any event no longer than the time of the vibrationalapproach of the string toward its electromagnet; the method by which weaccomplish this result consisting in shortening each tooth 34 by a spaceat least equal to the contact-thickness of the brush, and, of course,lengthening 'the high resistance section by an equal amount.

Fig. 9. not only shows the timbre controller, or means for switchingpulsations of higher frequencies into electromagnets 2 controllingstrings 1 of normally lower frequencies of vibration, but switchingdevices or means for putting these relatively low strings vibrated at anabnormally higher pitch. into the control of keys normally associatedwith such higher vibrations. The brushes of the disks 3 are shown asjoined by wircs 8 to the first row of a plurality of rows of contacts36. Across the face of these contacts are moved the brushes 37, so thatwhen said brushes are in touch with said first row of contacts. thepulsations of each disk 3 are communicated to the electromagnets 2directly in line with the same, the wires 8 joining said brushes withsaid electromagnets. The contacts of the first row being wired (at theback of the board supporting the same. although not so shown) tocontacts in the second row at a specified distance away toward the bassend of the board, and the contacts in this second row being wired tocontacts in the third row at a still further specified distance towardthe bass end, when the brushes 37 are removed to such second or thirdrow of contacts, the pulsations of higher frequen- I cies will betransmitted to the electromagnets controlling the lower strings, asalready described.

In the timbre controller as illustrated in Fig. 2, the brushes 37 are intouch with the third row of contacts 36, and each of these contacts iswired to a contact in the first row two octaves therefrom, ortwenty-four spaces distant, the heavy black line 38 indicating suchconnection for a single note, and the pulsation disk selected being thedisk whose rate of pulsation is that of the note (7, and to which inFig. 2. C is applied. The brush thereby connected with the same istherefore that of the note G a heavy line 8 indicating its connectionwith the electromagnet 2 of a string 1 whose normal pitch is C From thiselectromagnet passes another heavy line 8. indicating a wire orconductor, to a brush 40. which wire. if said brush were in touch withthe last row of contacts 41, would put the C pulsations under thecontrol of the key (7 the wires 9 joining said last row of contacts tothe contacts 11 swept by the brushes 12 (Fig. 3), of the keys-14c. We,however, consider in addition it objectionable, usually, to have a basskey controlling a treble note, and consequently prefer to have thelatter put under the control of a key normally associated with the samepitch. This is the function of the switching devices comprising saidbrushes 12 and contacts 40, 41. These switching devices are much likethe above described timbre controller, except that they reverse thedirection of switching. The timbre controller switches the higherpulsations from the pulsation device down to the electromagnets of lowerstrings, and the switching devices 12, 40, 41 switch the current fromthe lower electromagnets up to the higher keys. This is indicated for asingle note by the wire represented by heavy line 42. which is seen toconnect the brush of the C string and electromagnet to the wireindicated by heavy line 9 joined to the con tact 11 of the key In otherwords, the pulsations are delivered to the C electromagnet and string.but are placed under the control of the C key. Hence by the use of boththe timbre controller and the switching devices 12. 410, 41, the pitchesof the notes controlled by the keys are apparently not changed butsimply the timbre thereof.

' Fig. 1 illustrates the apparatus by which our complete method or artof producing tones is carried into effect. Here the parts set forth inFig. 2 comprise the left-hand section of the figure, or the backinstrument as we term the same, the part of the apparatus in thevicinity of the key board being called the front instrument, but bothparts being preferably combined within a single case. Referring now toFig. 1. in addition to what has been already described are rheostats 45introduced into the circuits between the pulsation device brushes andthe timbre controller of both the front and back instruments. Eachrheostat a5 is provided with a plurality of degrees of resistanceconnected with the different contacts 46 over which its associated brush47 is adapted to be swept. When such brushes are brought toward the rowof contacts to which the wires 8 are joined, such resistance is more andmore out out until such row is actually reached, 49 indicating suchresistance-units. lVe have discovered, however, that the proportioningof such resistanceunits is no easy matter; that it does not follow thatbecause a certain increment of resistance added to one circuit willreduce the loudness of a note a specified degree. an equal incrementwill equally reduce an adjoining note, nor that double such incrementwill make the same note one-half as loud.

We have in fact been obliged to work out the problem for each note ofthe entire instrument, giving each the several different degrees ofloudness Which we desired such note to have, until we have eventuallysucceeded in plotting a series of curves representing the relativeintensities of the notes, there being a separate curve for each degreeof loudness.

While the rheostats are useful inmodulating the loudness of musicproduced by the instrument as a whole, they are as or perhaps morevaluable in varying the quality of tones emitted. \Vhen the-front andback instruments are being simultaneously played,as they are adapted tobe by the single bank of keys 14,-and through the suitable shifting ofthe timbre controller the two instruments are made to produce tones,those of one instrument differing very materially from those of theother in timbre or quality, the resultant effects can be changed byvarying the adjustment of the rheostats of one or both instruments, sothat one timbre shall be subdued and the other more pronounced anddominant. This will give a quite different effect from that producedwhen both are of equal loudness, and permits of asystem of permutationsresulting in a great range of tone color. It is evident that with thehammers striking the front strings and thus eliciting their fundamentaltones, the front electromagnets drawing from said strings certain tonequalities, and the rear electromagnets vibrating the rear stringsdifferently still and causing them to give forth yet other tonequalities, the resultant music produced through the depression of keysof a single bank will equal and even surpass that of an orchestra. If itbe desired to play the front instrument alone, it is only necessary toentirely withdraw the brushes 40 from the contacts 41,

and thus to cut off all flow of current to the back instrument. Towithdraw the dampers from the back strings, their electromagnets 30 arejoined by wires 32 to the wires 9 leading from the brush contacts 11,while a common wire 31 joins them to the source 5. From the other poleof source 5 a wire 13 and brush 12 complete the circuit to contacts 11.r

The term set as herein applied to strings, notes, sonorous bodies, andthe like, refers only to a plurality of bodies having different pitchestuned in scale-relations to each other, and does not refer to thatplurality of sonorous bodies tuned to the same pitch, commonly calledunisons. The term sets of pulsations also used herein, is meant toexpress pulsations of different frequencies imposed upon or delivered toone and the same electromagnet.

From the foregoing description taken in connection with the drawings itwill be seen that a given sonorous body, string or other, can under thisconstruction and arrangement be simultaneously vibrated in three ways:by the hammer blow through the depression of the key; electrically,through the depression of the key with the circuit closer completing thecircuit of the magnet for that key and its interrupter disk rotating; bythe use of the timbre controller and depression of another key, whichthrough said controller is caused to bring into circuit with theelectromagnet associated with such sonorous body 'another interrupterproducing a greater number of interruptions and consequent pulsations,and hence giving a greater number of vibrations. If, therefore, thesethree modes be employed simultaneously there will be produced from thesame string or sonorous body three sets of vibrations, andas aconsequence a tone incident to the hammer blow, that is to say, a tonehaving the pitch for which the body is tuned and the overtones andquality incident to such hammer blow; there will also be educed a toneincident to the electrical vibration of the body at the same rate as isoccasioned by the hammer blow, but giving the even and sustained toneincident to perfect uniformity and constancy of vibration; and therewill be, lastly, a similarly uniform and constant vibration of the bodyat a frequency greater than that occasioned by either the hammer blow orthe pulsations produced by the interrupter normally associated" withsuch body, that is to say, there will be superimposed upon the othervibrations of said sonorous body a set of vibrations incident tobringing into electric circuit with it an interrupter producing afrequency of pulsation greater than that produced by the interrupternormally assoeiated with the magnet of such body.

A single set of vibrations may be imparted to the sonorous body by thehammer blow or electrically; or it may be vibrated by the hammer blowand simultaneously electrically vibrated at the same frequency;

or it may be vibrated by the hammer blow at the frequency which producesthe fundamental tone for which such body is tuned, and simultaneouslyvibrated electrically at a greater frequency; or it may besimultaneously vibrated at two different frequencies through theelectrical pulsations produced in the electromagnet associated with suchbody. Finally, the three sets of vibrations may be simultaneouslyproduced. It is in this sense that the expression sets of pulsations isemployed in the following claims.

From the fact that the individual tones, and the distinctive tonequalities incident to each different set of vibrations, are clearlypresent and distinguishable when the several sets of vibrations areimpressed upon the sonorous body, it is evident that each set preservesits identity notwithstanding the presence of the others. The resultantvibration is apparently a compound or complex vibration, and the severaltones .with their peculiar tone qualities, blend more or. less with andmodify each other, or produce a composite tone efiect, but each separatetone is nevertheless distinguishable and in itself apparently unchangedby the presence of the others.

The term vibrating freely is here used as meaning vibrating at the rateor with the fre'quencynatural or normal to the given string or sonorousbody, or in other words is intended to differentiate such vibration froma forced or abnormal vibration.

As prolongation of the electrical impulse and consequent magnetic actionin producing a swing or movement of the vibrating body beyond the timerequired to complete such swing, is found to interfere with or destroythe perfect sound effect sought, it is to be understood that while suchimpulse should equal in duration the time required for such swing ormovement of the vibrating body, it should not exceed that time. Theclaims are hence to be read with this understanding, and whereexpressions such as impulses the duration of each of which is made toequal the time consumed by said sonorous body in its vibrational swingin one direction, and the like, occur, they are to be read orinterpreted accordingly.

We claim 1. The art of educing musical tones, which consists inpercussively vibrating a tuned sonorous body, and simultaneouslysubjecting the same to the attraction of an electro magnet receivin twosets of electric pulsations, one set of a frequency to educe the tonefor which said body is tuned and another set of a higher frequency.

2. The art of educing musical tones from a tuned sonorous body, whichconsists in simultaneously delivering to an electro-mag net located inattractive relation to such body, a plurality of distinct andindependent sets of electrical pulsations of different frequenciesbearing a recognized musical re lation, those of one set having thefrequency of the free vibrations of such tuned sonorous body.

3. The art of educing musical tones from a tuned sonorous body, whichconsists in simultaneously delivering to an electromagnet located inattractive relation to such .7 body a plurality of distinct andindependent sets of electrical pulsations of different frequenciesbearing a recognized musical relation, those of one set having thefrequency of the free vibrations of such tuned sonorous body, and othershaving higher frequency.

4. The art of educing a variety of tone qualities from a single tunedbody, which 5. The art of educing a variety of tone qualities from asingle set of key-controlled tuned sonorous bodies embracing a number ofoctaves, which consists in producing a set of electric pulsations foreach said body, corresponding in frequency to the normal vibrationsthereof when producing the fundamental tone for which it is tuned;impressing pulsations of higher frequency up on a body tuned to lowerpitch, thereby causing said body to vibrate at a frequency other thanthat which produces its fundamental tone and temporarily putting I thebody of normally lower pitch under the control of the key primarilycontrolling the body of normally higher pitch.

6. The art of educing from a tuned body a plurality of tonal efiectssimultaneously, which consists in delivering to an electro: magnet inattractive relation to said body a plurality of sets of electricpulsations of different frequencies, and selecting said frequencies bymeans other than the sonorous body. I

7. The art of producing musical tones,

which consists in imparting to a tuned sonorous body a series ofimpulses the duration of each of which is made to equal the timeconsumed by the said sonorous body in its vibrational swing in onedirection.

8. The herein-described art of educing musical tones from magneticallyattractable sonorous bodies tuned to a musical scale, which consists insimultaneously delivering to the actuating magnet of a selected one ofsaid bodies a plurality of sets of electric pulsations, those of one setcorresponding in frequency to the free vibrations of said body, andthose of the other set being of higher frequency.

9. The art of educing from a tuned sonorous body varying tonal effects,which consists in delivering to an electromagnet in attractive relationto said body a plurality of sets of electric pulsations of differentfrequencies; selecting said frequencies by means other than the sonorousbody itself; and varying the resistance to passage of current to saidmagnet.

10. The art of producing tonal effects from a plurality of bodies tunedto the same pitch, which consists in delivering to electro magnets eachin attractive relation to its associated body, electric pulsations.those delivered to the magnet associated with one invention, We havehereunto set our hands body being of the frequency of the free vithis6th day of January, 1910.

brations of such body, and those delivered MELVIN L. SEVERY.

to the other magnet being of a higher fre- GEORGE B. SINCLAIR. 5 quenoythan the free vibrations of said Witnesses:

bodies. A. B. UPHAM,

In testimony that we claim the foregoing EDWARD G. THOMAS.

